Phytopathogenic fungi may affect a variety of plant organs, such as leaves, stems, fruits and seeds. Infected plant fruits are usually unfitted for sale, and an infection of leaves or seeds may alter plant development or germination, causing significant reduction of productivity. Therefore, fungal infections may result in substantial economic losses. The control of fungal infections of crops is thus a major economic issue.
Conventional chemical fungicides commonly used to protect crops against fungal infection present the drawback to be highly pollutant for the environment, especially for soil and water supply. Moreover, these products may be toxic for humans.
Other agents target fungal pathways, such as, for example, metabolic pathways. Sterol biosynthesis inhibitors, such as, for example, triadimenol, have been used to control fungi. Moreover, WO2006/066974 describes the use of methionine synthase inhibitors for the treatment of fungal diseases of crops.
However, such inhibitors present a large spectrum of action, and may thus have an inhibitory effect on fungi naturally present in the soil, thereby inducing a disturbance of soil ecosystem.
There is thus a need for a fungicidal composition specific of fungi attacking a plant of interest, while not impacting fungi of the soil.
In response to a fungal infection, plants synthesize antifungal defense molecules, such as, for example, phytoalexins. The inventors showed that a phytopathogenic fungus may adapt its metabolism to protect itself against the toxic effects of these molecules, especially via the activation of signalization pathways. Developing an inhibitor of said pathways may thus be a promising way for protecting plants without any disturbance of the soil ecosystem.
Moreover, for human health sake, it could be of interest to reduce the amount of fungicide applied on crops. Indeed, as fungicide applied on crops may be found on food, precautionary principle requires minimizing the amount of fungicide used.
The inventors herein identified agents that potentiate the action of plant defense molecules, such as, for example, inhibitors of signalization pathways activated in a phytopathogenic fungus in response to a plant defense molecule. Due to this potentiating effect, it is possible to reduce the amount of fungicide applied on crops.
The present invention thus relates to a composition or product comprising such a potentiating agent. In one embodiment, the invention focuses on destructing fungi when the fungi actually is attacking a plant of interest, while not impacting fungi of the soil, thus avoiding any disturbance of the soil ecosystem.